Electric-circuit closer for burglar-alarms



UNITED STATES PATENT OFFICE.

\VILIQIAM C. THOMPSON, OF MINNEAPOLIS, MINNESOTA, ASSIGNOR TO THEIVESTERN ELECTRIC COMPANY, OF CHICAGO, ILLINOIS.

ELECTRIC-CIRCUIT CLOSER FOR B URGLAR-ALARMS.

SPECIFICATION forming part of Letters Patent No. 465,602, dated December22, 1891.

Application filed October 19 1889. Serial No. 327,535. (No model.)

T0 at whom it may concern.-

Be it known that I, WILLIAM C. THOMPSON, a citizen of the United States,residing at Minneapolis, in the county of I-lennepin and State ofMinnesota, have invented a certain new and useful Improvement inElectric-Circuit Closers for Burglar-Alarms, (Case 1,) of which thefollowing is a full, clear, concise, and exact description, referencebeing had to the accompanying drawings, forming a part of thisspecification.

My invention relates to electric burglaralarms of the class adapted tobe operated by the moving of the window-sash in its frame.

The object of the invention is to provide a circuit-closer for electricburglar-alarms that shall be simple in its construction and operation.

Heretofore a circuit-closing device has been used consisting in a metalstrip attached to the windoW-frameand bearing a roller which pressesagainst the edge of the window-sash and adapted to rotate when the sashis moved. The said roller is of metal, except a segment of theperiphery, which is of insulating material. Mounted on a rubber blocksecured to the carrying-strip is a contact-spring, which presses on theperiphery of the roller. \V hen the sash is raised, the roller isrotated and the metal portion brought under the spring, and whenloweredthe insulating portion isbronght under said spring to break the circuit,as shown in Letters Patent No. 198,529, granted John Young December 25,1877, for electric burglar-alarms.

My invention consists in the combination of a flexible strip or springcarrying at its end a roller which is provided with a lateral pinadapted to engage with a hooked contact spring orbrush mounted onaninsulated block secured to the flexible strip.

I have illustrated my invention as attached to the frame of a window,the corrugated roller pressing against the edge of the window-sash andin position to close the circuit of the battery and gong, the poles ofthe battery being connected to the flexible strip and contactspring,respectively.

My invention will be more readily understood by reference to theaccompanying drawings, in which- Figure 1 is an elevation of a portionof a window frame and sash provided with an electric circuit-closerembodying my invention. Fig. 2 is a view of my circuit-closer detached.

Like parts are indicated by similar letters of reference throughout thedifferent figures. A roller a is carried on the flexible strip 1) androtates on the pivot 0, provided thereon. Said roller a is provided witha lateral pin (t and extends through an opening 6 in the flexible strip17, said opening 6 being of a size and shape to allow the lateral pin inthe side of the roller to pass through also, but only on one side of thepivot, as shown. The roller is thus allowed to make only the greaterpart of a revolution on its axis.

Mounted on a rubber block it, secured to the flexible strip 1;, is ahooked contact-spring Said hooked spring 1' is placed on the side of-theroller a which is provided with the lateral pin (1, but does notnormally make contact therewith. The hook 011 the end of thecontact-spring t serves to make the contact with the lateral pin (1 inthe roller a more certain, to limit the motion thereof, and in a measureto lock the said pin and roller in position when in engagementtherewith.

In Fig. 1 the window-sash j is supposed to have been raised and theroller a is shown in position to complete the circuit of the battery andgong through the pin (1 and hooked contact-spring If the sash should belowered, as indicated by the dotted lines, the roller a would berevolved and the pin (I brought around against the front side of theflexible spring t, as shown at 00. In this position the circuit of thebattery and gong would be opened and consequently the alarm silenced. Itwillbe seen that the window j may be raised and left at nearly the fullheight and yet the alarm be in position to give warning if the sash israised still higher. This is accomplished by simply raising the sash toa height greater than that desired and then lowering it a shortdistance, thus leaving the circuit open and yet still in a position togive an alarm if the window should be raised. The periphery of theroller is preferably corrugated, so as to increase the friction betweenthe roller and sash, to insure rotation when the sash is raised orlowered. The friction between the sprin and lateral pin keeps theirsurfaces bright and clean, thus rendering an electrical connectionbetween the terminals of the battery sure.

I preferably place my device in a mortise near the top of the lowersash. It is evident, however, that my device may be used either inconnection with the upper or lower sashes of a window.

Having thus described my invention, I claim as new and desire to secureby Letters Patent 1. The spring mounted upon the windowframe oppositethe edge of the sash, and a metallic roller provided with a metalliclateral pin, said roller being carried at the free end of said springand projecting through a slotopening therein to bear against the edge ofthe window-sash, in combination with the hooked contact-spring whichcarries the roller, said hooked spring being placed in the path of thesaid lateral pin to form contact therewith and hold the said wheel fromrotating after the window-sash is raised a fixed distance, wherebyelectrical contact is maintained between the spring carrying the rollerand the hooked spring, substantially as shown and described.

2. The circuit-closer consisting in the combination, with the springcarrying the roller, of the hook i, insulated therefrom, a lateral pinprovided upon the roller and adapted to be brought against the hook toclose the contact therewith when the roller is rotated in one direction,and a stop in the path of the pin for limiting the movement of theroller, substantially as and for the purpose specified.

In witness whereof I hereunto subscribe my name this 2d day of October,A. D. 1889.

WILLIAM C. THOMPSON. \Vitnesses:

GEO. W. TEITSWORTH, WM. I-I. BLODGETT.

